1. Field of the Invention
The present invention relates to a suction cap device and a liquid jetting apparatus.
2. Description of the Related Art
Generally, a liquid jetting apparatus having liquid jetting head which jets a liquid is provided with a cap member which is made an elastic member and is capable of covering a liquid jetting surface, of the liquid jetting head, having nozzles formed therein. The cap member has a suction port communicating with a suction mechanism such as a suction pump, etc.; and during a purge processing for preventing any unsatisfactory discharge or jetting from the nozzles, the cap member covers the liquid jetting surface of the liquid jetting head and receives air bubble and/or a liquid having increased viscosity which is/are sucked from the inside of the nozzles by the suction pump. Then, the liquid jetting apparatus causes the cap member to be away from the liquid jetting surface, and drives the suction pump to discharge (discard) the liquid received in the cap member.
When the suction operation by the suction pump is carried out while covering the liquid jetting surface with the cap member, a tightly closed space (sealed space) defined by the inner wall surface of the cap member and the liquid jetting surface is depressurized. At this time, there is a fear that the cap member might be deformed due to the difference in pressure between the inside and outside of the sealed space, and that the deformation of the cap member might result in formation of a gap between the cap member and the liquid jetting surface. To address such a situation, a cap chip is conventionally known which is accommodated or arranged in the cap member and which restrain or regulate the deformation of the cap member. Since the cap chip needs to have rigidity sufficient for regulating or restraining the deformation of the cap member, the cap chip is disposed on the entire surface, of the cap member, on which the liquid is received, and the cap chip has a through hole for causing or guiding the liquid inside the cap member to flow to the side of the suction port. For example, Japanese Patent Application laid-open No. 2008-221836 (see FIG. 3) describes a cap member provided on an ink-jet recording apparatus having an ink-jet head, and accommodating a cap chip which has through holes of a same diameter and formed to penetrate through the cap chip in the thickness direction of the cap chip.
However, in the cap chip provided on the recording apparatus having the ink-jet head described in Japanese Patent Application laid-open No. 2008-221836, the through holes are formed to have a small diameter such that the liquid can flow easily through the through holes by the capillary action. However, since the diameter of the opening, of each of the through holes, on a surface the cap chip surface opposite to the side of the suction port (opposite-side surface) becomes also small, it is difficult for the ink to flow into the through holes. On the other hand, although it is possible to conceive a method for increasing the diameter of the through holes to thereby enlarge the diameter of the opening of the through holes on the opposite-side surface, this makes the diameter of the through holes be increased entirely in the thickness direction of the cap chip. Consequently, it is not possible to secure the rigidity sufficiently enough to restrict or regulate the deformation of the cap member and, at the same time, the capillary force acting on the ink flowing through the through holes is reduced.